You might pick up a couple of lb/ft. of torque with an aftermarket exhaust, but you are more likely to pick up hp. The reason that our motors will never pick up a serious amount of torque is because of the design of the motor and the displacement. European Evo/e46 m3's may have 90-100 more crank hp than US m3's, but they only have approximately 30 more lb/ft. of torque. This is why without forced induction it would be extremely difficult to out-accelerate an e39 m5 because it has so much damn torque. Modified Domestic owners love the saying, and no matter how annoying it may be, "there is no replacement for displacement," or something to that effect. For the Mozart, it can drone at highway speeds, but more than likely you will be accelerating too often to notice it. Make no mistake, this exhaust is LOUD. Email me directly if you have any more questions.